Re: [PATCH] slab: add flags in cache_show
From: Kassey Li
Date: Thu Oct 23 2025 - 23:07:26 EST
在 10/17/2025 6:50 PM, Vlastimil Babka 写道:
On 10/17/25 08:48, Kassey Li wrote:
Flags info is useful to check the slab type.Many of the flags are represented by files in /sys/kernel/slab/<cache>/
for example, _SLAB_RECLAIM_ACCOUNT:
0x50100 _SLAB_PANIC _SLAB_RECLAIM_ACCOUNT _SLAB_CMPXCHG_DOUBLE
Signed-off-by: Kassey Li <kassey.li@xxxxxxxxxxxxxxxx>
If you miss some, we could add it there. Changing slabinfo output could
break some users and the raw hex value is not a stable representation of the
flags anyway.
may you review this draft change according your suggest ? if ok, i will share v2 change.
diff --git a/mm/slub.c b/mm/slub.c
index b1f15598fbfd..619f446d2251 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -9033,6 +9033,12 @@ static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
}
SLAB_ATTR_RO(slab_size);
+static ssize_t slab_flags_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", s->flags);
+}
+SLAB_ATTR_RO(slab_flags);
+
static ssize_t align_show(struct kmem_cache *s, char *buf)
{
return sysfs_emit(buf, "%u\n", s->align);
@@ -9480,6 +9486,7 @@ SLAB_ATTR(skip_kfence);
static struct attribute *slab_attrs[] = {
&slab_size_attr.attr,
+ &slab_flags_attr.attr,
&object_size_attr.attr,
&objs_per_slab_attr.attr,
&order_attr.attr,
---
mm/slab_common.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 932d13ada36c..f43239211e69 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1083,7 +1083,7 @@ static void print_slabinfo_header(struct seq_file *m)
* without _too_ many complaints.
*/
seq_puts(m, "slabinfo - version: 2.1\n");
- seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
+ seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> <flags>");
seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
seq_putc(m, '\n');
@@ -1112,9 +1112,9 @@ static void cache_show(struct kmem_cache *s, struct seq_file *m)
memset(&sinfo, 0, sizeof(sinfo));
get_slabinfo(s, &sinfo);
- seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
+ seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d 0x%-8x",
s->name, sinfo.active_objs, sinfo.num_objs, s->size,
- sinfo.objects_per_slab, (1 << sinfo.cache_order));
+ sinfo.objects_per_slab, (1 << sinfo.cache_order), s->flags);
seq_printf(m, " : tunables %4u %4u %4u",
sinfo.limit, sinfo.batchcount, sinfo.shared);